1. Field of the Invention
This invention generally relates to a bicycle hub axle adapter that is configured to be inserted into a bicycle hub having a hollow hub axle.
2. Background Information
In the case of mountain bikes and other bicycles that travel on rough terrain, a hub axle with a large diameter is sometimes used to increase the rigidity of the hub. Many users of such bicycles prefer a quick release mechanism for removing and changing wheels. Also different bicycles have different specialized quick release mechanisms. However, since the skewer shaft of a conventional quick release mechanism is typically small, the conventional quick release mechanism that a user wishes to use is incompatible with a large-diameter hub axle and cannot be installed in the large-diameter hub axle.
A solution to this problem is to use a hub axle adapter inserted into the space between the large diameter hub axle and the skewer shaft of the conventional quick release mechanism. An example of such a hub axle adapter 20 is shown in FIG. 6. This hub axle adapter 20 has a pair of frame contacting sections 20b, a pair of hub axle contacting sections 20c and a recessed section 20e. The frame contacting sections 20b are inserted into dropouts (not shown) provided on a rear end or a front end of the bicycle frame such that it contacts the bicycle frame. The hub axle contacting sections 20c each have an external circumferential surface 20d that contacts an internal peripheral surface of the hub axle. The recessed section 20e is provided to reduce the weight of the hub axle adapter, and is formed between two hub axle contacting sections 20c. The recessed section 20e has a smaller diameter than the hub axle contacting sections 20c. The frame contacting sections 20b, the hub axle contacting sections 20c, and the recessed section 20e are formed as a one-piece integral unit. When viewed along an axial direction of the hub, an insertion hole 20a for inserting the skewer shaft (not shown) is provided in a center portion of the frame contacting sections 20b, the hub axle contacting sections 20c, and the recessed section 20e. 